Conventionally, there has been proposed a hysteresis comparator circuit as described in, for example, Patent Literature 1. It can be considered that the hysteresis comparator circuit is used to convert, into a pulse signal, an output signal of a magnetoelectric conversion element for converting the change of magnetic flux whose direction changes periodically with the rotation of the rotator into an electric signal. The hysteresis comparator circuit converts the output signal of the magnetoelectric conversion element into the pulse signal, based on the large/small relationship between a threshold and the output signal of the magnetoelectric conversion element.